Liquid paraffin

• BPLiquid Paraffin
• JPLiquid Paraffin
• Ph. Eur.Paraffin, Liquid
• USP–NFMineral Oil

Mineral oil; heavy mineral oil; white mineral oil; heavy liquid petrolatum; liquid petrolatum; paraffin oil; paraffinum liquidum; Drakeol; Marcol

Mixture of refined liquid saturated hydrocarbons obtained from petroleum · [8012-95-1]

Polymer, mixture or material of variable composition — no single molecular formula applies.

Semi-solid base, emollient

Typical concentrations: 1–32% emulsions · up to 95% ointments · Dosage forms: Semi-solid

Used mainly in topical preparations as an emollient and as the oil phase of emulsions and ointments, and in ophthalmic ointments. It is also used as a lubricant in capsule and tablet manufacture, as a vehicle and solvent, and in oral emulsions as a laxative. Typical concentrations: ophthalmic ointments 3–60%; otic preparations 0.5–3%; topical emulsions 1–32%; topical lotions 1–20%; topical ointments 0.1–95%.

A transparent, colourless, oily liquid without fluorescence in daylight. It is practically odourless and tasteless. Light liquid paraffin (light mineral oil) is a separate, lower-viscosity grade.

Relative density

0.827–0.890 (Ph. Eur.); light grade 0.810–0.875

Viscosity (dynamic, 20 °C)

110–230 mPa·s (Ph. Eur.); light grade 25–80 mPa·s

Solubility

practically insoluble in water, ethanol (95%) and glycerin; soluble in ether and chloroform; miscible with most fixed and volatile oils (not castor oil)

Acidity/alkalinity

neutral to litmus

Liquid paraffin oxidises on exposure to heat and light, forming peroxides and an unpleasant odour; antioxidants such as butylated hydroxytoluene or tocopherol may be added. It may be sterilised by dry heat. Store in an airtight container, protected from light, in a cool, dry place.

Incompatible with strong oxidising agents.

Obtained by distillation of petroleum: the high-boiling fraction remaining after removal of the lighter fractions is refined (for example by acid treatment or catalytic hydrogenation), decolourised and deodorised.

Topically it is regarded as non-toxic and non-irritant. Prolonged oral use as a laxative can reduce absorption of fat-soluble vitamins, cause anal seepage and irritation, and aspiration (especially in infants, the elderly and bedridden patients) can cause lipoid pneumonia. Injection has caused granulomatous reactions (paraffinomas).

Observe normal precautions for the quantity handled. Eye protection and gloves are recommended; spills are slippery and should be cleaned up promptly.

Permitted as a food additive in the USA under specified conditions (21 CFR 172.878). Included in the FDA Inactive Ingredient Database (ophthalmic, oral, otic, topical, transdermal and vaginal preparations) and in non-parenteral medicines licensed in Europe.

Light liquid paraffin (light mineral oil); hard paraffin; white soft paraffin (petrolatum); mineral oil and lanolin alcohols.

Grades differ mainly in viscosity, so the pharmacopoeial grade should be specified; the light grade spreads more easily and is preferred in sprays and some lotions. Gelled liquid paraffin (with polyethylene) forms a hydrocarbon gel ointment base.